线形离子阱囚禁199Hg＋实验的光学系统设计

利用Zemax软件为线形离子阱囚禁199 Hg＋实验设计了一套光学系统,该系统包括两部分,即光学激发系统和荧光收集系统。光学激发系统由202 H g无极谱灯和激发透镜组组成。激发透镜组将202 Hg无极谱灯的直径为15 mm的圆形面光源整形成23 mm ×4 mm的矩形光去激发199 H g＋能级跃迁,从而使其辐射出荧光,再利用荧光收集系统去收集该荧光。荧光收集系统由收集透镜组、滤波片和光电倍增管组成。设计结果表明：该收集透镜组可以很好地将荧光发光面成像在直径为23 m m的光电倍增管上,具有较高的荧光收集效率,约3％。经物理系统实验,结果表明,该光学系统满足实验要求且具有较高的信噪比,其值约为20。这为高性能线形199 H g＋微波频标的工程应用提供了基础。     

Comparison experiments of neon and helium buffer gases cooling in trapped ~(199)Hg~+ ions linear trap

The influences of different buffer gas, neon and helium, on199Hg+clock transition are compared in trapped199Hg+linear trap. By the technique of time domain’s Ramsey separated oscillatory fields, the buffer gas pressure frequency shifts of199Hg+clock transition are measured to be(d f /dPNe)(1/ f) = 1.8 × 10-8Torr-1for neon and(d f /dPHe)(1/ f) = 9.1 × 10-8Torr-1for helium. Meanwhile, the line-width of199Hg+clock transition spectrum with the buffer gas neon is narrower than that with helium at the same pressure. These experimental results show that neon is a more suitable buffer gas than helium in199Hg+ions microwave frequency standards because of the199Hg+clock transition is less sensitive to neon variations and the better cooling effect of neon. The optimum operating pressure for neon is found to be about 1.0 × 10-5Torr in our linear ion trap system.     

Co-Mn-Al层状双氢氧化物催化臭氧氧化水中有机污染物的活性

采用共沉淀法制备了Co-Mn-Al层状双氢氧化物,并将其用于以硝基苯为目标污染物的催化臭氧降解反应中.结果表明,Co-Mn-Al层状双氢氧化物存在时,硝基苯的降解和矿化效率较单独臭氧氧化系统显著提高.采用加入羟基自由基捕获剂(叔丁醇)和电子顺磁共振检测(5,5-二甲基-1-吡咯啉-N-氧化物为捕获剂)的间接、直接方法,...     

有序介孔锰氧化物催化过氧化氢降解水中诺氟沙星

采用硬模板法制备了有序介孔氧化锰,并用过氧化氢氧化诺氟沙星的降解率及其抗菌活性变化评价了其催化活性.研究发现,有序介孔锰氧化物表现出较高的催化活性;低pH有利于提高其催化活性.与单独过氧化氢氧化过程相比,有序介孔锰氧化物的存在明显减弱了诺氟沙星的抗菌活性.叔丁醇对催化体系的抑制作用表明有序介孔锰氧化物促进了过氧化氢分解生成羟基自由基.通过对诺氟沙星在催化过程中的分解产物鉴定,提出了可能的分解途径.     

Paul阱中199 Hg+离子囚禁与射频共振检测

射频囚禁源作为Paul阱实验装置重要部分之一,对离子的囚禁性能影响很大. 为了满足离子囚禁稳定性以及提高离子囚禁势阱深度,设计和制作出两套囚禁离子的射频源和射频共振吸收检测电路. 利用不同频率的射频源及相应检测电路在双曲线型离子阱实验装置中成功地囚禁了¹⁹⁹Hg⁺和N⁺₂离子得到了它们的射频共振吸收信号.     

Evaluation of the frequency instability limited by Dick effect in the microwave ~(199)Hg~+ trapped-ion clock

In the microwave ~(199)Hg~+ trapped-ion clock, the frequency instability degradation caused by the Dick effect is unavoidable because of the periodical interrogating field. In this paper, the general expression of the sensitivity function g(t)to the frequency fluctuation of the interrogating field with Nπ-pulse(N is odd) is derived. According to the measured phase noise of the 40.5-GHz microwave synthesizer, the Dick-effect limited Allan deviation of our ~(199)Hg~+ trapped-ion clock is worked out. The results indicate that the limited Allan deviations are about 1.75 × 10~(-13)τ~(1/2) and 3.03 × 10~(-13)τ~(1/2) respectively in the linear ion trap and in the two-segment extended linear ion trap under our present experimental parameters.     

Paul阱中囚禁离子信号直流抛出检测方法

在原有射频扫幅抛出检测方法的基础上,通过恒定射频场幅度仅增加直流电场幅度的方法实现了Paul阱中离子的抛出.采用的直流抛出方法成功地对囚禁在Paul阱中199Hg+离子进行了检测,并克服了射频扫幅抛出检测方法采集大质量数离子的信号的线性、精度、稳定度不理想的缺陷,采集到信号的信噪比较高,达到了100以上,这为获得囚禁离子的各种动力学参数提供了较好的实验数据.     

Microwave-Optical Double-Resonance Spectroscopy Experiment of 199Hg＋ Ground State Hyperfine Splitting in a Linear Ion Trap

We report a spectroscopy experiment of the ^199Hg＋ ions are optically pumped by a discharge lamp and splitting is measured to be 40507347996.8（0.1）Hz by line width as 30mHz is also observed. This progress ion frequency standards. ground state hyperfine splitting in a linear ion trap. The cooled by helium buffer gas. The ground state hyperfine the mierowave-optical double-resonance method. A nsrrow builds the foundation for the realization of trapped ^199Hg＋